1. Field of the Invention
The invention relates generally to endoscopic type medical devices incorporating a body or housing to which is attached some actuating mechanism at one, proximal end and a working mechanism at the other, distal end, the working mechanism being suitable for either applying surgical ligating clips, use as forceps, etc. More particularly, the invention relates to an improvement in endoscopic type instruments which enables the instrument to operate in its normal mode only after a trigger mechanism is selectively activated.
2. Description of the Prior Art
Surgical ligating or hemostatic clips ar used to ligate blood vessels, ducts or other tissue during surgery. The terms "ligating" and "hemostatic" are used interchangeably herein. The clips generally have two parallel legs which are crimped in place about the tissue to be ligated and are applied with a clip applying instrument used to crimp the clip legs together. When first introduced many years ago, each clip to be applied had to be picked up individually by the jaws of a so-called "manual" clip applying, forceps-type instrument, often from a separate clip cartridge or dispenser prior to each use. While manual appliers are still used, subsequent instruments produced were "automatic" clip appliers (some of them disposable) and incorporated a clip dispenser as part of the clip applying instrument. Since different surgical procedures require the use of varying numbers of ligating clips, the automatic appliers come pre-loaded with different numbers of clips and in varying sizes. See, for example, U.S. Pat. No. 4,712,549 (Peters et al.), assigned to the assignee of this invention.
In addition to the clip dispenser, the automatic instruments generally include a pair of jaws for receiving, holding and crimping a single clip at a time and a feeding means for feeding a clip from the dispenser to the jaws. The jaws and feeder are activated in proper sequence by an activating means usually including a pair of handles coupled mechanically to the feeder and jaws.
It has been noted by those skilled in the art that the use of hemostatic clip appliers in endoscopic surgical procedures requires some additional precautions over and above those available in appliers described above which are primarily intended for use in open surgical procedures. For example, in endoscopic surgical procedures it is desirable for the surgeon to select the point in time when a ligating clip is to be fed between the jaws of the clip applier. This prevents the possibility that a clip would be waiting between the jaws of a clip applier (as in some conventional clip appliers used in open surgical procedures) and thereby run the risk of becoming dislodged and falling uncontrollably into the body. Retrieving such accidentally dislodged clips in open surgical procedures is relatively easy, if necessary, although much more difficult in endoscopic procedures.
The assignee of the present invention has a pending U.S. patent application Ser. No. 375,174, filed Jul. 3, 1989, now a FWC of U.S. Pat. No. 07/684,139, which discloses an automatic hemostatic clip applier which has a unique operating mechanism employing a "ratchet" yoke mechanism interposed between the activating handles of the applier and the clip feeding and jaw closing structures in order to prevent undesired feeding of the clip to the jaws during a portion of the operating cycle of the applier. This instrument automatically enables the feeding of a clip at a certain part of the cycle of operation of the applier. The present invention is an improvement on this aforementioned device in that it gives the user control over the feeding of the clip and, consequently, produces an applier suitable for use in endoscopic as well as open procedures. The present application incorporates the prior application by reference in its entirety.
It is an object of this invention to produce a clip applier which enables the surgeon to select the point in time at which a ligating or hemostatic clip is to be placed in proper position for use.
It is a further object of this invention to produce a ligating or hemostatic clip applier suitable for use in endoscopic surgical procedures